1. Field of the Invention
This invention relates to a volatile organic compound treatment apparatus which is useful for decomposition of vapors of organic solvents which, when released into the atmosphere, become harmful, for example, toluene, xylene and styrene, and other organic compounds (hereinafter abbreviated as “VOC”), that is, volatile organic compounds.
2. Description of the Related Art
Painting factories, semiconductor factories or printing factories use large quantities of organic solvents. It is known that VOC discharged into the atmosphere from such factories gives serious influences against the atmospheric environment, for example, it forms a harmful organic fine particle upon reaction with sunlight or ozone or it increases the ozone concentration in the atmosphere. For that reason, it is strongly demanded to recover VOC and make it harmless.
For the purpose of recovering VOC, a gas concentration rotor formed in a honeycomb shape supporting hydrophobic zeolite or active carbon is developed and diffused. VOC having been adsorbed and concentrated by the gas concentration rotor is decomposed by a catalyst or a combustion apparatus, made harmless and then released into the atmosphere.
An apparatus for decomposing VOC by electric discharge is also developed. The apparatus for decomposing VOC by electric discharge is constructed such that a corrugated cardboard-like VOC adsorber is interposed by a pair of electrodes along with an insulator. Before the VOC adsorber has adsorbed VOC and become saturated so that it cannot thoroughly adsorb VOC, an alternating current voltage of from 5 to 7 kV is applied between the electrodes to generate electric discharge, VOC is desorbed from the VOC adsorber by the generated electric discharge plasma, and the desorbed VOC is further decomposed into water and carbon dioxide. During the decomposition treatment of VOC by electric discharge, the gas to be treated is made to flow in the same amount as in the case where no electric discharge is generated. Incidentally, if the gas is stopped during the decomposition treatment of VOC by bringing electric discharge into contact with the VOC adsorber, the gas treatment cannot be carried out because only one VOC adsorber is present.
Incidentally, a phenomenon in which the VOC adsorber has adsorbed VOC and become saturated so that it cannot thoroughly adsorb VOC in the gas to be treated is called “breakdown” of the VOC adsorber (for example, see Japanese patent application publication no. 2002-126445, Patent Document 1).